Janome makes great portable lightweight machines called Gems. Several different types of Gems too. Be sure and look at the Kenmore machines. They are made the same as Janome, Sears here sells Janome along side the Kenmores.
If you happen to find a Singer 301, it is really a better machine then the Featherweight as far as having more umph and it's a great quilting machine. It's lightweight enough to carry to classes.